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Trypanosoma cruzi , the agent of Chagas disease exhibits significant genetic diversity. This parasite is divided into six discrete typing units (DTUs) where T . cruzi I (TcI) is the most widespread in the Americas. TcI genotypes have been associated to domestic and sylvatic cycles of transmission (TcI Dom and sylvatic TcI). Due to the importance of the enzootic transmission, we determined the frequency of TcI genotypes present in Rhodnius prolixus captured in different regions of the palm A . butyracea to understand the ecology of the disease and the importance of A . butyracea palms as ecotopes of R . prolixus . Forty A . butyracea palms were sampled (base crown, mid-point and crown) capturing 105 individuals identified as R . prolixus by morphological and molecular barcoding. We conducted molecular detection and typing of T . cruzi across 59 individuals. The results showed that all the insects were infected with TcI; 28.57% were sylvatic TcI, 12.38% TcI Dom and 15,24% mixed infections (TcI Dom /sylvatic TcI). Statistical analysis showed a similar behavior between TcI Dom and mixed infections in the mid-point and at the crown of the palm, being more frequent in the crown, while sylvatic TcI does not seem to have a specific association with any of the sampled areas. These findings are consistent with other studies showing high mobility of the insect vector between different ecotopes, increasing the need to develop improvements in the programs of disease control. [ABSTRACT FROM AUTHOR]

Trans-sialidase (TS) is a polymorphic protein superfamily described in members of the protozoan genus Trypanosoma . Of the eight TS groups recently described, TS group I proteins (some of which have catalytic activity) are present in the distantly related Trypanosoma brucei and Trypanosoma cruzi phylogenetic clades, whereas other TS groups have only been described in some species belonging to the T. cruzi clade. In the present study we analyzed the repertoire, distribution and phylogenetic relationships of TS genes among species of the T. cruzi clade based on sequence similarity, multiple sequence alignment and tree-reconstruction approaches using TS sequences obtained with the aid of PCR-based strategies or retrieved from genome databases. We included the following representative isolates of the T. cruzi clade from South America: T. cruzi , T. cruzi Tcbat, Trypanosoma cruzi marinkellei , Trypanosoma dionisii , Trypanosoma rangeli and Trypanosoma conorhini . The cloned sequences encoded conserved TS protein motifs Asp-box and VTVxNVxLYNR but lacked the FRIP motif (conserved in TS group I). The T. conorhini sequences were the most divergent. The hybridization patterns of TS probes with chromosomal bands confirmed the abundance of these sequences in species in the T. cruzi clade. Divergence and relationship analysis placed most of the TS sequences in the groups defined in T. cruzi. Further examination of members of TS group II, which includes T. cruzi surface glycoproteins implicated in host cell attachment and invasion, showed that sequences of T. cruzi Tcbat grouped with those of T. cruzi genotype TcI. Our analysis indicates that different members of the T. cruzi clade, with different vertebrate hosts, vectors and pathogenicity, share the extensive expansion and sequence diversification of the TS gene family. Altogether, our results are congruent with the evolutionary history of the T. cruzi clade and represent a contribution to the understanding of the molecular evolution and role of TS proteins in trypanosomes. [ABSTRACT FROM AUTHOR]

Highlights: [•] T. cruzi seroprevalence in children under 16 years old in Chaco, Argentina is 26%. [•] After 5 years of Benznidazole treatment, seroconversion rates were not evident. [•] PCR assays are useful for early detection of treatment failure. [•] DTUs TcV have be involved in most children infection. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to characterise Discrete Typing Units (DTUs) of 28 isolates of Trypanosoma cruzi from humans (15), triatomines (9), and opossums (4) in the state of Paraná, southern Brazil. For this purpose, we analysed the size polymorphism at the 3′ end of the 24Sα ribosomal RNA gene (rRNA) and the restriction fragment length polymorphism (RFLP) of the partial 5′ sequence of the mitochondrial Cytochrome Oxidase subunit II gene (COII). Band patterns of the isolates were compared with reference samples of T. cruzi I (Silvio X10 and Col 17G2), T. cruzi II (Esmeraldo and JG), T. cruzi III (222 and 231), T. cruzi IV (CAN III), T. cruzi V (SO3 cl5), and T. cruzi VI (CL Brener). Our results confirmed that rRNA analysis is of limited use for assessing T. cruzi DTUs. COII RFLP analysis was suitable for screening, but for one isolate it was necessary to determine the COII partial sequence to identify the DTU. Only one of the isolates from humans belonged to T. cruzi I; 13 isolates belonged to T. cruzi II and one to T. cruzi III. The four isolates from opossums and five isolates from triatomines were identified as T. cruzi I. Four isolates from triatomines showed patterns of both T. cruzi I and II, indicating mixed infections. This study contributes to the characterisation of the dynamics of T. cruzi populations in southern Brazil. [Copyright &y& Elsevier]

Abstract: Trypanosoma cruzi the aethiological agent of Chagas disease, a complex zoonoses that affects the American continent is a genetically variable parasite subdivided into six Discrete Typing Units (DTUs). T. cruzi I is the most prevalent DTU affecting the northern countries of America with sporadical cases in the southern countries. T. cruzi I has shown great genetic diversity showing plausible subdivisions needed for this group. Recently, TcI has gained novel importance because of the lately discovered relation with cardiomyopathy manifestations that raises the importance of establishing subdivisions within this DTU. [Copyright &y& Elsevier]

• Mepraia spinolai naturally infected with Trypanosoma cruzi from rural areas of Chile • Discrete typing unit (DTU) TcI was predominant in single and mixed infections • Higher parasitic load found in vectors infected with more than one DTU • Blood meal sources do not show clear patterns regarding parasitic load or DTU Mepraia spinolai, a wild vector of Trypanosoma cruzi in Chile, is an abundant triatomine species that is frequently infected by the parasite that causes Chagas disease. The aim of this study was to determine if the parasitic load of T. cruzi in M. spinolai is related to its blood meal source and the infecting DTUs of T. cruzi. The vector was captured in rural areas. In the laboratory, DNA was extracted from its abdomen and T. cruzi was quantified using qPCR. Real time PCR assays for four T. cruzi DTUs were performed. Blood meal sources were identified by real-time PCR amplification of vertebrate cytochrome b gene sequences coupled with high resolution melting (HRM). Trypanosoma cruzi was detected in 735 M. spinolai ; in 484 we identified one blood meal source, corresponding to human, sylvatic, and domestic species. From these, in 224 we were able to discriminate the infecting DTU. When comparing the parasitic loads between the unique blood meal sources, no significant differences were found, but infections with more than one DTU showed higher parasitic loads than single infections. DTU TcI was detected in a high proportion of the samples. Higher parasitic loads are related to a greater number of T. cruzi DTUs infecting M. spinolai , and this triatomine seems to have a wide span of vertebrate species in its diet. [Display omitted] [ABSTRACT FROM AUTHOR]

The relationship among genetic diversity of Trypanosoma cruzi and clinical forms of Chagas disease remain elusive. In order to assess the possible association between different T. cruzi Discrete Typing Units (DTUs) and the clinical pictures of the disease, 205 chronic patients from Salta province, Argentina, were analysed. One hundred and twenty-two of these patients were clinically categorized as: cardiac 38.5% (47/122), digestive 15% (18/122), cardio-digestive 16% (20/122) and asymptomatic 30% (37/122). From each patient, blood samples were taken for both, Polymerase Chain Reaction (PCR) targeting kDNA and blood culture analyses. The presence of T. cruzi kDNA was detected in 43% (88/205) of the patients. T. cruzi DTUs were identified in 74% (65/88) of the kDNA positive patients by PCR-hybridization using specific probes. We detected the presence of DTUs TcI, TcII, TcV and TcVI. Single infections (i.e. presence of only one DTU in the sample) were detected in 38.64% of the samples (34/88), while mixed infections were 35.23% (31/88). TcV was the most prevalent DTU (60.3%- 53/88). The association analyses showed, for the first time to the best of our knowledge, that TcV and TcVI were associated with the digestive form of Chagas Disease (Fisher p =.0001). Unlabelled Image • TcV and/or TcVI infections were statistically associated to digestive syndromes. • All the possible clinical forms of Chagas Disease were found. • Mixed infections (more than one DTU) were frequent in the studied patients. [ABSTRACT FROM AUTHOR]